Sand core forming apparatus



Dec. 24, 1935. 'AQ sTAHN v SAND CORE FORMING APPARATUS Filed June-18, 1954 Patented Dec. 24, 1935 PATENT OFFICE i Aaimant SAND CORE FORMING APPARATUS Albert Stalin, Hanover,

Application June 18, 1934, Serial No. '131,155

, In Germany June- 27, 1933 zrclaims. (ci. zz-io) My invention refers to sand -core and mold forming apparatus and more especially to apparatus of the kind described, in which the sand or the like contained in a sand container is suppiied to the core box or mold by means of compressed air. 1

My invention vhas particular reference to the means for feeding theair'to the sand container and it isan object of my invention to provide 'air ,0 feeding means which are more efilcient than those hitherto in use.

The container, in which a supply of molding sand or the like is stored, is hitherto supplied with compressed air through an opening or openy5 ings in the cover of `.such container. It is well known to every person skilled in this art, that on admitting compressed air through this opening,

cavities or funnel-shaped channels will form in the sand, which extend substantially in a straight line -from the air inlet to the sand outlet formed "in the bottom of the container. These channels thus follow .the path of least resistance. It is equally known'that thesefunnel-shaped channels prevent a considerable part of the sand from be- 5 ing expelled from the container, more especially in the case of sand containing-clay or so-called green molding sand, for the compressed air will frce the sand against the side walls of the container, and the sand will then stick to these walls,

3 instead of being expened by the air current. It

is for this reason that stirrers have been-provided in these containers; however these stirrers require a separate drive consuming energy and are exposed to rapid Wear. The use of these and -35 other contrivances has not suiced to enable the compressed air to expel all of the sand.

The means provided according tothe present invention solve this problem in the simplest and most eflicient manner Without requiring any energy, since the invention utilizes the repulsion effect exerted by the compressed air entering the container on a flexible tube, the free end of which is caused, by this repulsion effect, to continuous- 45 ly change its position relative to the body of sand in the container, so that no ldistinct channels can be formed therein.

Alternatively, instead of using iiexible tubes, I may use rigid tubes movably suspended in the container so as to allow them to move under the 5prepulsion effect exerted on their ends by the compressed air.

In the drawing aixed to this specication and forming part thereof, two embodiments of my invention are illustrated ditically by way 55 of example. l

In the drawing, Fig. 1 is a vertical axial section of a funnelshaped sand container equipped with a exible air admission tube.

Fig. 2 is a. similar view of a modification, in 5 which the air is admitted through two movably suspended rigid tubes.

Referring to the drawing and rst to Fig. 1,

. I is the funnel-shaped sand container, 2 is the 'execute jerky movements, whereby the free end 20 ofthe tube is continuously displaced on the surface of the body of sandin the container, thereby preventing the formation of the funnelshaped channel indicated in the sand by dotted lines.

In the modification shown in Fig. 2, the inner end of the pipe 4 is branched and to the branch pipes 6 Aare fitted rigid tubes 1 by means of ball couplings 8, which may also be replaced by other movable coupling `means including short rubber tube ends or the like. i

Here also, when the compressed air is admitted through pipe 4, the compressed air entering the tubes 'l will cause them to wander above or in the sand, thereby loosening the-sand and preventing the formation of a funnel-shaped channel.

Obviously the movable sand vadmitting means shown and described will direct the compressed air onto ever varying points of the body of sand, Y thereby preventing any sticking to the walls and the formation of definite cavities or channels.- The term wall as used in the claims is intended to include the removable cover of the sand container. 45

' I wish it to be understood that I do not desire` to`be limited to the exact details of construction shown and described for obvious modifications Will occur to a person skilled in the art.

In the claims afilixed to this specication no selection of any particular modification of the invention is intended to the exclusion of vother modications thereof and the right to subsequently make claim to any modication not covered by these claims is expressly reserved.

I claimzv 1. In an apparatus of the kind described the combination, with a sand container, -of a compressed air admission tube passing through and iixed inV a wall of saidfcontainer, the end of said tube, which projects into said container, being free under the repulsion eil'ect exerted on it by the compressed air, to be automatically displaced relative to the sand in the container.

by the compressed air,.to be automatically dis-- placed relative to the sand in the container.

ALBERT STAHN. 

